# Statistics and planning

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• Created by: pk
• Created on: 31-03-13 12:18

Why knowledge in statistics is important ?

1) when quantitative data are involved in experiments it's important to know if the measurements we have are of any significance

2) when planning an experiment we should know what data to be collected

Summarising data
Mean median mode

Normal distribution
If a frequency histogram is drawn from a large sample of data and if it falls In to a symmetrical bell shaped graph it is known as hotmail distribution.

Standard deviation
Gives the idea of how clumped the individual measurements are around the mean value. If the standard deviation is higher the datA are more widely distributed. 67% of measurements within normally distributed data lie within +- 1 standard deviation .
95% within the range of mean - + standard deviation.

Significance levels ; decisions about the significance of the results of any statistical test are based around the 5% significance level. Results are said to be significant if they occur less than 5% of the time

If result is significant at the 5 % level you can reject the null hypothesis and accept the alternative hypothesis.

Students…